Certified Flight Instructor - Flight Instructor Airplane Practice Exam

What force is described as imparting a change in the velocity of a mass?

1. Work.

2. Power.

3. Thrust.

4. Drag.

The correct answer is: Thrust.

Thrust is the force that propels an aircraft forward and is responsible for changing the velocity of the mass of the aircraft. In the context of flight, it is produced by the engines, whether they are jet engines or propellers, and acts in the opposite direction to drag. The primary role of thrust is to overcome drag and any other opposing forces to accelerate the aircraft or maintain its flight speed. While work is related to the transfer of energy when a force is applied over a distance, and power is related to the rate at which work is done, they do not specifically describe a force that changes velocity. Drag, on the other hand, is a force that opposes motion. Therefore, thrust is the only force mentioned that specifically serves to change the velocity of a mass in flight. This is a fundamental concept in aerodynamics and flight mechanics, essential for understanding how aircraft operate.